Fuel pump



June 9, 1959 T. H. THOMPSON FUEL PUMP 2 Sheets-Sheet 1 Filed NOV. 30,I954 gag/V l N VENTOR 727/1/1. 77/0Mp5a/v,

ATTORNEY June 9, 1959 T. H. THOMPSON FUEL PUMP 2 Sheets-Sheet 2 FiledNov. 30, 1954 ATTORNEY United States Patent FUEL PUMP ApplicationNovember 30, 1954, Serial No. 472,118 4 Claims. (Cl. 103-38) Thisinvention relates to a fuel pump, and more particularly to a fuel pumpfor a fuel injection system of the type described in my copendingapplication Serial No. 383,538, filed October 1, 1953, now Patent No.2,809,868.

In fuel pumps of the type to which the present invention is directed,three important features must be given consideration. The first is thecost of construction. In order for fuel injection systems to beuniversally adopted on automobiles today, the cost of the systems mustbe comparable to the present carburetor injection system.

Second, the system must have a long life, for example, comparable tooperation of an automobile for 50,000 miles or the system will not beadopted.

Third, the system must have a reliability or uniformity of operation.This is particularly important at-idling speeds, for, at such speeds,the quantity of fuel injected with each stroke of the pump must besubstantially the same as at every other stroke of the pump, otherwisethe engine will not perform smoothly.

The pump according to the present invention is satisfactory with respectto all of the considerations mentioned above. Economy is provided byconstructing the pump bellows from Belleville washers with a very simplebut effective interconnecting arrangement. Thus, the expensive Sylphonbellows are eliminated as well as other very complicated pumpingmechanisms.

A long life is designed into the pump, particularly into the criticalbellows by providing a novel arrangement for interconnecting theBelleville washers, which permits the Belleville washers a limitedfreedom of movement with respect to each other and with respect to theinter connecting arrangement so as to prevent unnecessary stresses inthe washers thereby reducing failure of the washers by fatigue.

Uniformity and reliability are provided both by the interconnectingarrangement referred'to above and by the bellows actuating linkagewhich: at idling speedslmaintains the bellows substantially completelycollapsed. By this arrangement the bellow amount of fuel when the enginecal speed.

It is, therefore, an object of the present invention to provide a fuelpump which is economical to construct, has a long life, and is reliableand uniform in its performance. It is a further object of theinvention'to provide a fuel pump in which the bellows thereforis'constructed from interconnected Belleville washers.

It is still a further object of the invention to provide aninterconnecting arrangement for the washers'which eliminates unnecessarystresses during operation of the pump.

It is another object of the invention to provide a bellows actuatinglinkage which maintains all of the bellows in collapsed condition whenthe engine throttle is closed. J

It is still a further object of the invention to'provide a bellows whichis substantially completely exhausted when in collapsed condition. 7

These and other objects will become more readily apoperates at its mostcritiv handles the minimum' parent from a consideration of the followingdetailed description of the invention taken in conjunction with thedrawings in which:

Fig. 1 is a cross-sectional view taken through the center of the pump,

Fig. 2 is a cross-sectional view taken through the center of one of thebellows, and

Fig. 3 is a cross-sectional view similar to Fig. 2 showing the bellowsin collapsed condition.

The pump is provided with a cylindrical casing 10 covered at the bottomwith a plate 12 and at the top with a plate 14. The plates are joined tothe cylindrical housing by bolts 16.

The top plate 14 is provided with outlet passageways 18 and intakepassageways 28 for each piston to be supplied with fuel (arrangement foronly two being shown). The outlet passageway 18 is provided with aone-way valve consisting of a check ball 20 biased by a spring 22. Theoutlet passageway is connected to an injector nozzle of some suitabledesign by a threaded member 24 having a bore 26. The injector nozzlepreferably is of the type shown in my copending application Serial No.383,538, filed October 1, 1953, now Patent No. 2,809,868.

Intake passages 28 are also provided with a one-way valve consisting ofa check ball 30 and a biasing spring 32 enclosed by a threaded member 34having an inlet bore 36. All of the inlet passageways are connected by acommon manifold 38 having a passageway 40 connected to a supply of fuel.

The intake passageway 28 and outlet passageway 18 are interconnected bya bellows arrangement 42. Upon expansion, or downward movement of thebellows, a vacuum will be created forcing fuel past check ball 30 intothe bellows. The collapse of the bellows will force the fuel out of thebellows to the injector nozzle through passageway 18. Instead of abellows, a piston and a cylinder arrangement or any other suitabledevice having a variable capacity can be used although not with thesuccess that is obtained from using the bellows according to thepresent'invention. The unique cooperation of the particular bellows withthe pumping linkage will be explained below.

In Fig. 1 the bellows are shown in the completely collapsed position andare actuated by a wobble plate 44 through an actuating ball 46. Thewobble plate 44 has an outer race 48 connected through bearings 50 tothe inner race 52. Inner race 52 is connected through linkage 54 to acontrol race 56. The control race is moved upwardly and downwardly by athrottle 58 connected through a link 60.

A spindle Fixedly mounted to the spindle is an arm 66 which drives theinner race 52 through a link 68 which is con nected to the race 52 andthe arm 66 at pivot points 70 and 72 respectively. It will be seen thatthe pivot point 72 forms a fulcrum point about which the wobble plate 44rotates in order to actuate the fuel pump bellows.

Referring to Figs. 2 and 3, each bellows 42 consists of a plurality ofBelleville washers which are connected at their larger and smaller edgesin the manner shown. The connections consist of a case-hardened slipperring 82 surrounded by a neoprene gasket 84, the whole being clamped toadjacent edges by a retainer band 86 which is crimped around theneoprene gasket. Retainer band 86 clamps the gasket snugly about themarginal portions of the washers to form a seal against fuel leakage.

The uppermost washer of the bellows is clamped in a 3 similar manner toa pump manifold chamber amount 88 which is provided with threads 90 sothat it can be screwed into the upper plate 14 of the fuel pump housing.

The lowermost Belleville washer is clamped to a bellows -bottom closuremember 92 with the same slipper ring, neoprenegasket and crimpedretainer. band arrangement. The bottom closure member 92 is provided"with a recess 94 to receive the actuating ball 46.

The manner of clamping the Belleville washers together as shown in Figs.2 and 3 of the drawings helps to provide for uniformity of operation.The Belleville washers are actually very small thin frusto conicalmembers. If they were connected at their edges by welding, as is done inother types of bellows, they would lose their uniform characteristicsand would distort undesirably. Furthenthe comparatively rigid connectionat the edges would cause unnatural bending stresses to occur during theoperation of the bellows which would tend to cause failure in thebellows by fatigue.

In order to eliminate these disadvantages and to permit the bellows toretain their uniform characteristics, the clamping arrangement as shownis provided. This clamping arrangement permits a freedom of movementbetween adjacent washers and eliminates the necessity of welding thewashers together.

When the bellows is expanded and collapsed,.a very minute movementoccurs at the edges of the Belleville washer. Therefore, the casehardened ring 32 is provided to engage the outer and inner edges of thewashers to permit that relative movement to occur without wearing outany of the clamping members.

The internal surafce of the bellows mayhave a coating 96 of neoprene orother suitable material to help seal the bellows against leakage, and tofill in voids created by the protruding clamping arrangement. With thisarrangement, it is possible for the bellows to be almost completelyexhausted when in the completely collapsed position shown in Fig. 3except for the central hole formed by the inner edges of each washerstage. The importance of this feature, particularly at idling speeds,will be demonstrated in connection with the description of the operationof the invention.

It may also be found to be advisable to coat the outside surface of thebellows with a neoprene coating 98. Without the coating 98, a small leakwould cause the internal coating to bulge during the intake stroke anddiminish the amount of fuel taken in on that stroke. However, with theouter coating any atmospheric air is prevented from leaking through tobulge the internal coating.

Operation In the position shown in Fig. l, the throttle is completelyclosed and the bellows are completely collapsed, taking the positionshown in Fig. 3. Movement of the throttle 58 in a counterclockwisedirection moves the end of the wobble plate 44 remote from the fulcrum72 in a downward direction. The bellows 42 immediately above that freeend of the wobble plate is forced by the spring action of the Bellevillewashers to open. The opening of the bellows creates a vacuum permittingfuel to be forced into the bellows by way of the intake passageway 28.

The spindle 62 is, of course, being rotated through pulley 64 at enginespeed. Spindle 62 causes therotation of the arm 66 carrying fulcrumpoint 72, as well as inner race 52. The rotation of inner race 52 whichhas been pivoted about fulcrum point 72 causes the tilted wobble plateto actuate all of the bellows 42 consecutively and in synchronism withengine 'speed. Further counterclockwise movement of the throttle arm 58causes greater tilting of the wobble plate and consequently greaterintake and injection of fuel.

It is important to note that all of the bellows are completely collapsedwhen the throttle 58 is closed. At this position the bellows can handlethe minimum amount 4 of 'fuel and, accordingly, the precise quantity offuel to be forced through the injector nozzles is most easilycontrolled. This can be best understood by considering fuel pumps of thetype shown in applicants copending application Serial No. 383,538, nowPatent No. 2,809,868, in which the bellows are greatly expanded atidling speeds. There, at idling speeds, the bellows are handling arather large quantity of fuel and control for idling is made much moredifficult because of the lack of'uniformity in the size andcharacteristics of the bellows. The effect of this lack of uniformity isproportionately decreased as the bellows handles smaller and smallerquantities of fuel.

In order further to enhance the idling characteristics, the internalcoating 96 is provided for the bellows. With this internal coating, thebellows approaches the theoretically perfect condition of a completelyexhausted bellows when the bellows is in completely collapsed condition.With this addedjfeatm'e the bellows handles the minimum possiblefuel'for operation at idling speeds.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and efficient embodiments of my invention,it should be Well understood that I do not wish to be limited thereto asthere might be changes made in the arrangement, disposition and form ofthe parts without departing from the principle of the present inventionas comprehended within the scope of theaccompanying claims.

I claim:

1. A wobble plate linkage for actuating a plurality of fuel-pumpingmechanisms centered on a circle comprising, a rotatable spindle,-awobble plate including an inner race and an outer race, bearingsconnecting said inner and outer races, said wobble plate beingconcentric with said spindle, means connecting said wobble plate toactuate the fuel pumping mechanisms, a control race mounted for rotationabout said spindle and for movement in an axial direction, controllinkage connecting said control race to the inner race of said wobbleplate, fulcrum linkage fixedly mounted to said spindle and connected tosaid inner race at a location remote from the connection between saidinner race and control linkage, said fulcrum linkage forming a fulcrumpoint for said wobble plate located on a projection of said circleparallel to said spindle, and means for moving said control race in anaxial direction.

2. In a fuel pump havinga plate provided with intake and outletpassageways, and a wobble plate actuating arrangement, a bellowsconstruction comprising, a plurality of interconnected stages, eachstage comprising two Belleville washers engaging each other at theirlarger edges, clamping means connecting said larger edges together topermit very small relative movement between said edges and said clampingmeans, means connecting the smaller edges of adjacent washers of eachstage together, means connecting the washer at one end of said bellowsto said intake and outlet passageways, and means closing the other endof said bellows, said last named means being adapted to be engaged bysaid wobble plate and internal coating means for providing asubstantially exhausted chamber in said bellows when in collapsedposition except for a central hole formed by the smaller edges of thestages.

3. A bellows comprising a plurality of interconnected stages, eachstagecomprising two Belleville washers engaging each other at their largeredges, clamping means connecting saidlargeredges of said washerstogether to permit very small relative movement between said edgesandsaid clamping means, said. stages engaging each other at the smalleredges of said washers, inner clamping means connecting said smalleredges together, coating means of a tapering thickness applied to theinner surface of said belows so that the interior of said bellows isfree from projections and when in collapsed position is substantiallycompetely exhausted except for a central hole formed'by the smalleredges of said stages.

4. A fuel pump comprising, fuel intake and outlet means, a plurality ofbellows connected to said fuel intake and outlet means, each of saidbellows comprising a plurality of stages, means on the internal surfaceof said bellows for providing a substantially completely exhaustedchamber in each of said stages when the bellows is in collapsedposition, a throttle lever, linkage means connecting said throttle leverwith said bellows for maintaining all said bellows fully collapsed whensaid throttle lever is closed, said linkage comprising a Wobble plateconnected to activate said bellows, a spindle, means for rotating saidspindle, fulcrum means connecting said spindle to said wobble plate toform a fulcrum for said Wobble plate on a projection of a circle onwhich the bellows are centered and means connecting the throttle leverto said wobble plate to pivot said plate about said fulcrum.

References Cited in the file of this patent UNITED STATES PATENTS

